Thursday 21 May 2009 12.31 EDT
First published on Thursday 21 May 2009 12.31 EDT

Four self-styled jihadists from New York planned to shock America by bombing two synagogues and bringing down a military plane in a coordinated attack conceived as revenge for the deaths of Muslims in Afghanistan and Pakistan, police said today.

The four men intended to carry out the attacks yesterday evening, planting what they thought were car bombs outside two Bronx synagogues and planning to detonate them at the same time as they shot down a plane with an anti-aircraft missile. But they were arrested amid an extraordinary display of police fire-power including an 18-wheel armoured truck used to block the suspects' vehicle.

New York's police chief and mayor warned today that the arrests underlined the ongoing danger of security threats against the city since 9/11. But the emerging details of the plot also illuminated the ability of federal authorities to infiltrate and track nascent terrorist activities.

According to the federal case against the men, the plot began to take shape as early as June last year. James Cromitie, a petty criminal with numerous convictions who is identified as the ringleader, is alleged to have begun making inquiries about buying explosives through a mosque in Newburgh, a town about 60 miles north of New York City where he lived. He said he was upset about the war in Afghanistan, as his father was an Afghan immigrant to the US.

Cromitie said he wanted to do "something to America", lamenting that "the best target was already hit" in an apparent reference to the World Trade Centre.

Even at that early stage the police was aware of his intentions. An informant posing as a member of an extreme Pakistani group was in contact with Cromitie at the mosque and remained closely associated with him, using hidden audio and video equipment to record conversations over the next 11 months.

In October, according to the charges, Cromitie began discussions with his three fellow conspirators whom he had met in prison. Two of the three are US citizens and the third Haitian; they are all converts to Islam.

The informant tracked the meetings of the four men, and arranged with FBI help to supply them with C-4 plastic explosives and a Stinger anti-aircraft missile. The men were unaware that all the weaponry, including the explosives which had been made up into a bomb-like object by FBI agents, was dud and utterly harmless.

Last month, the charges allege, the men began actively staking out Riverdale Temple and the nearby Riverdale Jewish Centre. They also surveyed the movement of military aircraft at Stewart air national guard base in Newburgh.

The plotters allegedly intended to create a "fireball that would make the country gasp". But there was no evidence that they were linked to a wider network of jihadists.

"The group was relatively unsophisticated, penetrated early and not connected to any outside group," said Charles Schumer, one of New York state's two US senators.

Despite the apparently naive nature of the conspiracy, Michael Bloomberg, mayor of New York, said it showed that threats against the city were "sadly all too real".

Raymond Kelly, the city's police commissioner, told a press conference outside the Riverdale Temple that the men had wanted to commit jihad. He quoted one of the four as saying "If Jews were killed in this attack, that would be alright."